This invention relates to compositions of the type comprising a crosslinkable film forming or matrix forming component and an amino crosslinking agent therefor. More particularly, the invention relates to thermosetting compositions of the aforementioned type wherein the cross-linkable film forming or matrix forming component is an oligomeric hydroxy functional phosphate ester and the crosslinking agent is an amine aldehyde compound. Compositions within the scope of the invention are particularly useful as coating compositions, most particularly as high solids coating compositions.
Because of increasingly strict solvent emissions regulations in recent years, low solvent emission paints have become very desirable. A number of high solids paint compositions have been proposed to meet these low solvent emission requirements. However, many of these compositions are deficient because of difficulty in application, slow curing rates, lack of flexibility, poor durability and low solvent and water resistance. Many of the proposed compositions have been particularly deficient as automotive topcoats, particularly when the topcoat is to include metallic flake as a pigment.
The deficiency in compositions including metallic flake results from undesired reorientation of metallic flake during application and curing of the coating. The flake reorientation results primarily because of the very low viscosity resins used in the paint compositions to accommodate high solids. The low thixotropy is not sufficient to immobilize the flakes which tend to redistribute themselves to show "reverse flop" and nonuniform distribution.
It has now been discovered that a novel class of hydroxy functional organophosphorous oligomeric esters are particularly suitable for the preparation of compositions which are crosslinked by amine aldehyde compounds. These compositions, which are particularly suited as coating compositions, afford high solids, low application viscosity, low bake coatings with excellent hardness, adhesion, gloss, solvent resistance, impact strength and elongation.